The name Joab in the Bible
The name Joab is assigned three times in the Bible, but the most famous Joab is David's nephew, the son of his sister Zeruiah. Both Joab and his brothers Abishai and Asahel have dominant functions in David's military (2 Samuel 2:18). Joab becomes a leader of the army but doesn't mind to do some of the killing personally. He murders general Abner after the latter killed Joab's brother Asahel (2 Samuel 3:27), Bathsheba's husband Uriah (2 Samuel 11), David's son Absalom (2 Samuel 18:14), and his cousin Amasa (son of David's other sister Abigail). On his deathbed David condemns Joab, and Solomon has him executed while he holds on to the horns of the altar (2 Kings 2:28-35, compare with 1 Kings 1:50).
Other Joabs are a man of Judah (1 Chronicles 4:14) and a family head among the returnees (Ezra 2:6).
Etymology of the name Joab
The name Joab consists of two elements. The first element is יה (Yah) = יהו (Yahu) = יו (Yu), which is the commonly accepted abbreviated form of יהוה, which is YHWH, the Name of the Lord. This very short abbreviation of YHWH also occurs in the names Jochebed and Jonathan.
The second element of the name Joab is אב (ab):
The name Joab means Yah Is Father. NOBSE Study Bible Name List reads Yahweh Is Father. Jones' Dictionary of Old Testament Proper Names reads Lord Father or Whose Father Is The Lord.